The invention relates generally to water filtration systems used to remove solid contaminants and particulates from water. More particularly, the invention relates to such systems used with storm water run-off collection basins, where the water is filtered through a filter media to remove contaminants and particulates prior to its entry into the general storm sewer system. Even more particularly, the invention relates to such systems having a removable primary filter means for initial removal of contaminants and particulates, filter media such as sand interposed between the primary filter means and the collection means, and a primary filter carrier receptacle means for separation of the primary filter means from the filter media.
Where settlement is not a practical or effective method for separating solid contaminants and particulates from a liquid, filtration by passing the liquid through a suitable filter impermeable to the solid contaminants is the preferred alternative. Filters constructed of cloth, paper, metal, or other similar materials are used--the filters being designed to have effective opening sizes smaller than the particular contaminants to be removed from the liquid. Since the filter traps the solid contaminants against its wall or membrane, the filter will usually clog due to particulate build-up over time, resulting in the need to clean or replace the filter. In storm water run-off applications, the solid contaminants are typically removed using sand or soil as the filter medium. The water is brought into the sand filter medium from the retention basin, made to flow through the sand and is collected by a perforated collection pipe for transport into the storm sewer system. The spaces between the individual sand particles have an effective opening size which traps any particulates greater than that size. Like other filters, sand or soil will become clogged over time and must be replaced. This is labor intensive, costly and time consuming, with the job being made even more difficult since the sites are often accessible to heavy equipment only with great difficulty.
To increase the effective life of sand filter media in storm water applications, it is known to provide ingress conduits, such as for example perforated PVC pipe, which enable the water from the collection basin to flow into the filter media. The ingress conduits are typically wrapped with a filter fabric which acts as a primary barrier to trap a majority of the particulates prior to the liquid entering the sand filter medium. While this does increase the life of the sand filter medium, the filter fabric itself will clog over time and must be replaced. While this is an easier task than total removal of the sand, it still entails the use of heavy equipment to dig up and replace the ingress conduit and filter fabric sock.
It is an object of this invention to provide a water filtration system adapted for use with storm water run-off collection basins, the water filtration system acting to filter solid contaminants from the liquid to a level whereby the water can be passed into the general storm sewer system.
It is a further object to provide such system which utilizes the standard filtration methodology incorporating sand as a secondary filter along with a primary filter to accomplish initial separation of the vast majority of solid contaminants from the water.
It is a further object to provide such system which incorporates a permanent housing encompassing the system, with the primary filter means being constructed of a flexible material and contained within a primary filter carrier receptacle means, whereby the sand filter means is separated from the primary filter means.
It is a further object to provide such a system where the primary filter means is removable from the primary filter carrier receptacle means and from the housing itself, whereby the primary filter means can be easily replaced when it becomes clogged with solid contaminants.
It is a further object to provide such a system where the housing is pre-constructed in modular form, whereby a number of modules can be joined to create water filtration systems of differing capacity.